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Patented June 6. 1882.-

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Witnesses UNIT D STATES PATENT Carma.

MOSES G. FARMER, F NE WPOR'I, RHODE ISLAND, ASSIGNOR TO THE UNITEDSTATES ELECTRIC LIGHTING COMPANY, OF NEW YORK, N. Y.

ELECTRIC INCANDESCENT LAMP.

SPECIFICATION forming part of Letters Patent No. 258,903, dated June 6,1882.

Application filed May 27, 1881. (No model.)

To all whom it may concern Be it known that I, IVIOSES G. FARMER, ofNewport, in the county of Newport and State of Rhode Island,haveinvented certain new and useful Improvements in ElectricIncandescent Lamps, of which the following is a specification, referencebeing had to the drawings accompanying and forming a part thereof.

Myinventiou relates to improvementsin that class of electric lamps inwhich a continuous conductor of carbon inclosed in an exhausted andhermetically-sealed transparent receiver is rendered luminous by thepassage of an electric current introduced into the said receiver bymetallic wires; and it consists in a method of manufacturing the saidlamps in such manner that they may be conveniently reopened and sealed,should it be necessary for any reasonsuch as for the insertion of newcarbons to gain access to the interior of the globe.

fusible orhighly-refractory substance-such as porcelain orearthenware-for the sealing material about the wires; and, secondly, anovel method offorming a plug orstopper containing the conducting wiresand of fitting the same to the globe.

Theinclosing globe which I employis formed with an enlarged portion anda narrower stem, something after the pattern of a Florence flask. Intothe open mouth of the stem is fitted bya 4o ground joint a stoppercontaining the metallic conductors, and composed of earthenware,porcelain, or some similar semi-vitrifiable substance which beforebaking is plastic and capable of being molded. In this stopper, whilestillin a plastic condition, the conducting-wires are embedded at such adistance apart that the ends of the carbon filament may be convenientlyattached to them. The stoppers, when formed about the wires, are placedin a potteryfurnace and baked in the ordinary manner uutil they haveacquired the solidity and impermeability of porcelain or earthenware,and by a vitrification oftheir fusible constituents have become verydense and hard. The subsequent steps of grinding and fitting into theglobe are the same as those pursued in the manufacture of ground-glassbottle-stoppers, the porcelain plugs being ground into the open neckuntil a perfectly air-tightjoint is formed.

In the accompanying drawing, which is referred to for an understandingof my invention, the globe is designated by the letter A, the stem orslightly-conical neck by B, and the stopper by O. This latter iscomposed of earthenware, porcelain, or other similar substance, and isformed in molds of plaster-ofparis, or by other proper means, and whilein the process of formation the wires D D are embedded in it at aconvenient distance apart, and to their projecting ends the carbon E isattached when by the action of a high temperature the stopper has beenthoroughly hardened and solidified and ground to fit into the open neckB.

Vhen dental porcelain, or a substance requiring a very high temperaturein baking, is employed for forming the stoppers, a metal must be usedfor the conductors capable of withstanding the intense heat, and forthis purpose I have made use of nickel, or an alloy containing nickel,which,on account of its highlyinfusiblenature audits comparativecheapuess, presents great advantages over all others. The refractorynature of the stoppers also makes it possible to extend them almostentirely up to the carboitclanips, by this means securing a longerjoint, and by protecting the wires pre venting the giving off of theoccluded gases from the said wires when they are heated by theincandescent strip.

As stated above,the substances employed in the formation of the stoppersmay be any that possess the characteristic qualities of porcelain, or ofa dense and homogeneous earthenware, and the more solid the character ofthe substance employed the more durable and perfect will be the jointswhich it makes with the glass and the metal conductors. As analternative method of closing the lamps with the stoppers,I may weldthem together by heat, and in this case,as well as in the 0thers,it willalways be found desirable to glaze or enamel the stoppers in order torender them the more impervious to air and other gases.

The steps subsequent to the forming and fitting the stoppers, as theyform no part of my presentinventiomand are now well understood by thoseskilled in the art, are not set out herein. Such consist in exhaustingthe globe of oxygen, providing for it suitable electrical connections,and the nrious processes for preparing the carbons.

Having thus described my invention, What I claim as new, and desire tosecure by Letters Patent, is

1. The method of forming a seal for the metallicconductorsofanincandescentlamp,which consists in embedding them in a plastic material,molding it to the desired shape, solidifying and hardening the samebyhcat, and then fitting the mass to an opening in the lamp, as setforth.

2. In an incandescent electric lamp, the combination, with a plug orstopper composed of porcelain, earthenware, or a similar material, ofconducting-wires of nickel or an alloy containing nickel, embedded inthe stopper, as described.

In testimony whereof I have hereunto set my hand this 23d day of May,1881.

MOSES Gr. FARMER.

In presence ol"' WILLIAM H. HAOKET'J, MARTIN P. TOBEY.

